This invention relates to a scissors, particularly a hairdressers' scissors of the type having between the two blades a pivotal connection consisting of a threaded pin and a steel nut having a projection, the threaded pin being non-rotatably connected to one of the two scissors blades.
In the conventional type of hairdressers' scissors the threaded pin is screwed mechanically into a threaded hole of one of the scissors blades. The thread of the hole is oversized so that the threaded pin is non-rotatably held. Due to this, the scissors blades engage each other with a predetermined pressure. The hairdresser is thereby not able to adjust the operation of the scissors which is dependent on the pressure with which the scissors blades engage each other according to his wish. There is in addition no possibility of readjusting the engaging pressure which decreases when the scissors wear out at the cooperating surfaces adjacent to the threaded pin or at the cutting edges. The conventional locking against rotation as is known in connection with pivotal connections consisting of a threaded pin and a steel nut cannot be used in connection with hairdressers' scissors, since due to the arrangement of a counter nut or a spring washer no sensitive adjustment of the operation of the scissors is possible. In addition, for such a locking against rotation one or two wrenches as well as a screw driver are necessary in order to rotate the nut, which are not always available.
A pivotal connection for scissors consisting of a threaded pin and a nut has, however, already become known from German Utility Model No. 76 09 410, in which the nut consists of plastic material and the thread thereof has a certain undersize so that the nut is seated on the thread of the threaded pin with a certain press fit. The nut additionally comprises an integrally formed smooth resilient rim by means of which it exerts contact pressure upon the neighboring scissors blade. By means of the rim the slope is intended to be compensated which in the case of scissors results from the fact that the scissors blades taper in the direction toward their tips. For such a scissors a loosening of the nut cannot be precluded with certainty because of the known creeping of plastic material under pressure strains.